Android 4.1 Jelly Bean is the slickest, fastest, most responsive release of Android yet. Here’s a list of the great features you have to look forward to when you get your hands on Android 4.1.

Jelly Bean isn’t as massive an overhaul as Android 4.0 Ice Cream Sandwich was, but it’s a significant release in its own right. Project Butter has made Android’s interface significantly responsive and largely banished lag.

Project Butter

Of all the new features in Android 4.1, this is the biggest improvement. “Project Butter” is the codename for all of the work that was done to make Android faster, smoother, and more responsive. Google declared a “war on lag,” and it shows. If you’ve used an underpowered device with an older version of Android, you’ll know that it sometimes stuttered and generally wasn’t as smooth as iOS was on iPhones. This has all changed – the changes even make Android more responsive on newer devices with good hardware, such as the Galaxy Nexus.

There’s a lot going on behind the scenes. The graphics pipeline is triple-buffered. All rendering is coordinated around a 16 millisecond VSync “heartbeat,” which is synchronized to touch events. When you touch the screen after Android has been idled for a while, Android instantly puts the CPU into high-performance mode. Android also anticipates where your finger will be when the screen refreshes.

Google Now

Google Now provides information to you without you specifically asking for it. For example, if you search for a flight number, a “card” will appear in Google Now with that flight schedule and Google will keep you updated. If you’re travelling, Google Now will show you live currency exchange rates. If you regularly leave for work at a specific time, Google Now will learn about your commute, provide traffic information, show an estimated duration for your trip, and suggest alternate routes. If you’re near a transit stop, Google Now will display the schedule of any upcoming busses or trains.

To access Google Now, touch the Home button and swipe up. Google Now has a lot of potential, and we’ll likely see Google expand on it in the future.

Voice Search

Android also includes voice search. Simply say “Google” out loud on the Google Now screen and ask your question or speak your search. You can also tap the microphone icon on the home screen’s Google search widget or in the Chrome browser.

Google’s voice search uses Google’s knowledge graph to provide you with answers to your questions. For some questions, such as “Who is the president of the United States?”, Google Now will speak an answer back to you. You can also ask questions such as “Do I need an umbrella today?”, as you can with Apple’s Siri.

If Google can’t provide an answer to your question, you’ll see Google search results for your query. This is integrated with Google’s other services, so you can ask for “pictures of marmosets” to see pictures of the animal or ask for a type of restaurant to see restaurants near you.

Expandable Notifications

Notifications in Android now show more information. You can expand them with your fingers to view more information – for example, you can view part of a screenshot you took or see the text of an email that just arrived. You can perform actions such as sharing an image or replying to an email directly from the notification drawer.

Predictive Keyboard

In addition to suggesting words as you type, Android’s keyboard now tries to predict the next word you’ll type before you’ve even started typing it. Suggestions appear above the keyboard – tap a word to select it.

Offline Speech Recognition

The speech recognition feature in Android allows you to enter text without having to type it on a touch screen, but it’s only worked with an Internet connection in previous versions of Android. In Jelly Bean, you can use speech recognition even if you’re offline – the offline dictionary for English is installed by default, but you can also install dictionaries for other languages from Android’s keyboard settings.

Google Maps can now be used offline, too — this also works in previous versions of Android with the latest versions of the Google Maps app. There was some offline support previously, but it was flaky and unreliable.

Face Unlock Liveness Check

The Face Unlock feature in previous versions of Android could be defeated by holding a photo in front of the camera. To help prevent this, there’s now an optional “Liveness check” you can enable – if you enable this feature, you’ll have to blink while unlocking your device with your face.

Features for Developers

Android 4.1 also includes some important new features for app developers. With “smart app updates,” Android devices can download only the bits of an app that have changed instead of re-downloading the entire application – this will speed up app updates and reduce the amount of data that must be downloaded.

Paid applications will also be encrypted with a device-specific key before they’re delivered to a device — this makes app piracy more difficult.